Arrangement for the audible receiving of undamped oscillations



April 1, 1 924. 1,489,158

Filed Aug. 18. 1922 Fly! WALTER SCHAFFER 831, hi; flum gy d resident of Berlin, Germany, have Patented Apr. 1, 1924.

UNITED STATES.

I 7' 1,489,158 PATENT OFFICE.

WALTER SCHLAFFER... F BERLIN,

GERMANY, ASSIGNOLR/ '10' GESELIJSGEAFT FUR DRAHTLOSE TELEGRAPHIE M. B. H. HALLESCHES, 0F BERLIN, GERMANY, A. COR- PORATION OF GERMANY.

ARRANGEMENT FOR THE AUDIBLE RECEIVING OF UNDAMPED OSCILLATIONE.

Application filed August 18,1922. Serial No. 582,618.

To all whom it may concern.

Be it known that I. WALTER SC'HAFFER, a citizen of-the Republic of Germany, and a invented certain new and useful Improvements in Arrangements for the Audible Receiving of Undamped Oscillations on which an application was filed in Germany, July 13, 1921',

No. G. 54,319, and of whlch the following is a specification, accompanied by drawings.

The invention relates to a receiving arrangement in wireless telegraphy and consists in this thatthe received energy is used for producing and controlling energy of a different frequency from the received frequency. The frequency thus produced may therefore. be kept so low that it is audible in a telephone so as to make possible the direct hearing of inaudible incoming high frequency.

In the drawing in which like reference numerals designate like parts in the various views;

Fig. 1 is a diagrammatic representation of a circuit arrangement embodying the invention, and

Fig. 2 is a diagrammatic representation of a modified circuit arrangement.

In the exemplification of the invention shown in Fig. 1, the reference numeral 1 designates the operating direct current source of a cathode tube 2, 3 the oscillating circuit of the tube with which a telephone circuit 1213 is inductively connected. 4 is a tube provided in the current supply circuit of the tube 2. Depending on the grid potential applied thereto, the tube t operates as a resist ance of varying value for the purpose of controlling the energy supplied to the generator tube 2. The received energy intercepted by the receiving antenna 5 is induced into the circuit 6 and rectified by means of any suitable rectifying arrangement 7. The direct current potential difierence existing between points 8 and 9 is always in proportion with the received energy. This direct current potential diiference is applied in anv suitable manner to the grid of tube 4 and controls therefore'the generator tube 2 in the above described manner. The arrangement may be such that the grid of tube 4 is connected in parallel with a resistance 10 through which the grid discharge may take place. If it is desired to cause the enegry applied to the generator tube 2 to be equal to zero when the received current is equal to zero, then it is usually advisable to apply a negative auxiliary potential to the grid of the tube 4. This auxiliary potential is obtained from the auxiliary battery 11. In the normal condition, i. e. when no signal is being received, the tube 2 does not generate oscillations because its supply circuit is interrupted by the infinitely large resistance of the tube 4. \Vhen the receiving starts, the resistance of tube 4 is reduced in proportion with the strength of the receiving current, thereby causing oscillations to be produced by the tube 2, the oscillations being controlled by the resistance of the tube 4. It will be seen that the intermediate circuit which is actuated by tube 2 may be tuned'to any desired wave length irrespective of theincoming receiving frequency.

If the oscillating circuit 3 which is coupled with tube 2 is tuned to an audible frequency then the undamped signals received on the antenna 5 may be heard directly in the telephone 13 after transmission from the oscillating circuit 3 through the agency of the coupling coils 12.

In the. embodiment. of the invention shown in Fig. 2, 1 again designates the operating current source of the cathode tube 2, and 3 denotes the oscillating circuit of the tube which is coupled with the telephone circuit 12-13. The grid of the generator tube 2 is connected at 14 with the intermediate circuit 3 through an inductive back coupling. The connection between the gridqcoupling coil 14 and the cathode of the generator tube 2 comprises a condenser 15. The receiving current occurring in the receiving antenna 5 will, as explained in connection with Fig. 1, be induced into the circuit 6 and rectified by means of any suitable rectifying arrangement 7 The potential difference between points 8 and 9 is applied to the condenser 15 in any suitable manner, and controls therefore the tube 2 in the well known manner. The arrangement is so constituted that the condenser 15 is connected in parallel with the resistance or grid leak 10 through which the grid discharge may take place. If it-is desired that the generator tube 2 shall not produce oscillations when the receiving current is equal to zero, then as in the previous case the grid of the tube' 4; d the condenser 15 have a negative auxiliary potential impressed u n them froman auxiliary battery. 11. n the normal condition 1. e. when no signal is being received, the tube does not produce oscillations because the grid potential is too high. When the receiving starts, the grid of the generator tube will have impressed u on it a stronger or weaker potential dependmg on the strength of the receivin current, thereby causing oscillations to %)8 reduced by the tube 2 and to be controlled by the receiving current. By means of this circuit arrangement also the undamped signals received in the receiving antenna 5 may be heard in the telephone 13 if the oscillating circuit 3 coupled with the tube 2 is tuned to an audible frequency.

The advantage of the present arrangement consists in this that without the use of transformer energy or mechanical buzzers or the like, inaudible oscillations may be rendered audible.

Having described, my invention what I claim is: i

1. An arrangement for the audible receiving of undamped oscillations comprising an audio frequency oscillation generator including a cathode tube, a grid for controlling the oscillations in said generator, a recelving circuit connected to the grid and a rectifier in the receiving circuit for causing direct current potential in proportion to the received energy to be impressed on the grid.

2. An arrangement for the audible receiv-.

ing of undamped oscillations comprising an audio frequency oscillation generator {on eluding a cathode tube, a grid for controlling the oscillations in said generator, a receiving cireuit connected to the grid and tuned to receive signals at radio frequency, a reetifierin the receiving circuit for causing direct current potential in proportion to the received energy to be impressed on the grid, and a detector, including a telephone, associated with the oscillation generator, so that a signal transmitted at radio frequency can be directly heard in the telephone.

3. An arrangement for the audible receiving of undamped oscillations. constructed to enable inaudible oscillations to be rendered audible Without the use of transformer energy or a mechanicalbuzzer or the like and comprising a single oscillation generator tuned to audio frequency, a receiving circuit for controlling the oscillating circuit of the oscillation generator, said receiving circuit being tuned to the inaudible frequency, a rectifier in the receiving circuit for causing direct current potential in proportion to the. received energy to be applied in controlling relation to the oscillating circuit, and a detector, including a telephone, assoeiated with the oscillating circuit of the generator;

masses 4. An arrangement for the audible receiving of undamped oscillations comprising an audio frequency oscillation generator, 2. three-element tube in the current supply circuit of the oscillation generator, a receiving circuit connected to the grid of the three-element tube, and a rectifier in the receiving circuit for causing. direct current potential in proportion to the received en-- ergy to be impressed on the id.-

5. An arrangement for the audible receiving of undamped oscillations comprising an audio frequency oscillation generator and means for controlling the generator including a cathode tube arranged in the current supply circuit of the generator and having a grid and a receiving circuit connected to the grid for charging the grid at apotential depending upon the strength of the receiving current, said receiving circuit being tuned to receive signals at radio frequency.

6. An arrangement for the audible receiving of inaudible oscillations, comprising an oscillation generator of audio frequency and means for controlling the generator including a cathode tube having a grid, a receiving circuit connected to the grid for charging it with a potential in proportion to the received energy, and agrid leak and grid condenser arranged in parallel in the receiving circuit.

7. An arrangement for the audible receiving of inaudible oscillations. comprising an oscillation generator of audio frequency, a variable resistance in the current supply circuit of the oscillation generator, and a receivin circuit for varying the resistance in sai supply circuit in a definite relation with the inaudible oscillations, so as to control the current in the oscillation generator in accordance with the received oscillations.

8. An arrangement for the audible receiving of unda-mped oscillations comprising an audio frequency oscillation generator including a cathode tube, a grid for controlling the oscillations in said'generator, a receiving circuit connected to the grid, a rectifier in the receiving circuit for causing direct current potential in proportion to the reccived energy to be impressed on the grid and means for applying an auxiliary potential to the grid to prevent generation of oscillations in the oscillation generator when no energy is being received.

9. An arrangement for the audible receiv ingofinaudible oscillations comprising an audio frequency oscillation generator including a cathode tube having a grid, a receiving circuit tuned to the inaudible oscillations, and a rectifier in the receiving circuit. said receiving circuit being connected to the grid to impress the rectified received energy on the grid.

. WALTER SCHAFFER. 

